It's hard to say without really knowing what was wrong with the guitar and what the prototype involves but my gut reaction is to say, start anew. It you are prototyping a new design you should be starting from scratch so you avoid the temptation to make the design/execution fit the materials or their situation.

A professional guitarist that I respected came to me to make a guitar. He wanted my to reuse parts from an old Yamaha to build it. I had to politely show him the door. Recycling is not appropriate to guitar building.

Professional guitar makers quite often have a "test mule" guitar or two, which new ideas are tested out on. I have a couple of guitars of different types that have had multiple tops on. If you do a decent job, very few people would be able to tell that a top (or back) had been changed. Here's one I changed recently. A few weeks ago it had a spruce top on...

This one was done as a "drop in" replacement top, keeping the original bindings.

It would be a shame to waste good wood so why not? If you can make it do want you want it to - go for it!Several people on the forum have retopped cheap guitars to make them sound better, and even putting a new top on a high quality instrument is not unheard of.

I very much appreciate the idea of respecting the wood, so I might very well reuse wood that I had already put to one purpose. To me, using reclaimed wood is part of that - using wood that spent a century as beams in a barn, for example, or spent a century on the bottom of a river. Mostly what goes wrong with an instrument for me is the finishing. I've routed off bindings and sanded back finishes to start again, I just do the best job I can. The decision would rest on the wood, and what I needed to do to it.

Your test mule looks nicer than some of my finished guitars.I'll probably try to salvage as much of the guitar wood as possible (back/sides) and try to refinish.

In teh worse case scenario, I'll paint it black.

Trevor Gore wrote:Professional guitar makers quite often have a "test mule" guitar or two, which new ideas are tested out on. I have a couple of guitars of different types that have had multiple tops on. If you do a decent job, very few people would be able to tell that a top (or back) had been changed. Here's one I changed recently. A few weeks ago it had a spruce top on...

DSCF0218s.jpg

This one was done as a "drop in" replacement top, keeping the original bindings.

Black paint is not really an easy way out. Most of my finishes are clear, so I asked a few guitar makers who do a lot more painting than me about how to go about a black finish. The unanimous advice was "don't do it"! They had a point, but I did it anyway. It's not easy. Lots of masking and scraping then reverse masking to level the different finish thicknesses, etc, etc. And black is not black. It's a gazillion different shades of grey!

Matthew Lau wrote:btw Trevor, one of these day's I need to get your book.

At this point I'm tripping all over my "test mules". They seemingly outnumber the successes!! I just can't bring myself to throw even failed tops away, but I don't know what I think I'm going to do with them. For example, I have some cutaway sides that were just too ugly to actually use on a "real" guitar. So I split them into two 1.75" rims for a double cutaway thinline guitar. Only I realized that I would need a neck that joined at the 17th fret, not 14, or it would look silly. So I can't use any of my standard necks. Do I make a new neck for these salvaged sides? And none of my reject tops or backs are double cutaway, so I'd be making those new. And the neck block, tail block, and linings will all have to be new...

The point is I never actually find a use for these rejects. But they sit around my shop nonetheless.

When I was traveling for work like a hobo, I'd be stuck in lonely 1 star motels in the middle of nowhere.When I was traveling for implant training, I'd be stuck in lonely 4 star hotels wishing for a guitar.

My goal for the test mule is:1. Experiment with stuff without shame--- hmmm, change the bracing on the back? Okay, pop that off with hot water!2. Be playable without any worries of getting it dinged up. I had a Korean roommate who was a total asshole. He'd grab my french polished guitar without asking, take a pick, and ding the hell out of it before I'd catch him. Later, he went to Hopkins to do Oral Surgery.

For that asshole who thinks he's being friendly, that flamenco guy who has one too many drinks, that neophyte wearing spiked leather that has no idea of how to treasure a guitar....it'd be nice to have a sacrificial lamb to protect the others.

-Matt

ps. Clay, could I bug you for pictures of your travel guitar?I'd love to make one with my test mule.

Hi Matthew, I'll try to post a few pics. I make them in various models - usually Martin clones. Here is a Dred and a double O. Personally I like the size 1 (not shown). (P.S. - I also made the picnic table they are sitting on out of Corian scrap.)

The neck is attached with a single socket head cap screw ( machine bolt) placed in the lower part of the heel which has been reinforced with a metal insert. The block in the body has a T nut for the bolt to screw into (not visible) and two pins mounted higher up to keep alignment. The truss rod is inset into the neck. I started making a neck pocket that is slightly more than the depth of the sides. It allows the fret board to be cut between the 12th and 13th fret and if angled back some can be used to set the action by using a shims (washers) around the bolt.

The body has a "port" in the bottom that is closed by a brace on the inside and a bolt run through the strap button. The end block is wide enough to include the port and has reinforcements glued behind it that also cradle the neck when it is inserted into the body. The machine bolt in the neck is reversed and screws into a T nut inserted into the upper reinforcement. The neck block (not shown) has a pocket that captures the peghead and keeps it secured at the upper body.